English

Pronunciation

Verb

In typography, leading (, rhymes
with heading) refers to the amount of added vertical spacing between lines of type.
In consumer-oriented word processing software, this concept is
usually referred to as "line spacing". Leading may sometimes be
confused with tracking,
which refers to the horizontal spacing between letters or
characters.

The word comes from lead strips that were put
between set lines. When type was set by hand in printing
presses, slugs or strips of lead (reglets) of appropriate
thicknesses were inserted between lines of type to add vertical
space, to fill available space on the page.

Text set "solid" (no leading) appears cramped,
with ascenders almost
touching descenders
from the previous line. The lack of white space between lines makes
it difficult for the eye to track from one line to the next, and
hampers readability.